The use of fluid shunting systems to shunt the cerebrospinal fluid (CSF) from the ventricles of the patient's brain to his heart or peritoneum in the treatment of hydrocephalus is common today. Many configurations of shunts and their indwelling pressure control elements have been invented, and the literature is full of their application experience. Many of these devices have membranes or diaphragm type pressure control elements whose characteristic gives a desired pressure flow curve for the CSF fluid that they are shunting. Relevant to the present invention are the shunt configurations of the Heyer-Schulte Company, which have a dome-shaped diaphragm pressure control element, and the Pudenz-Schulte Medical Company, which have an arched shape or mushroom-shaped pressure control element. These are described in their brochures and relate to the U.S. Pat. Nos. 4,364,395; 4,464,168; 4,552,553; and, 4,560,375. Furthermore, the Radionics Company has a shunt which uses a quasi-septum type pressure control element that has a silicone spoon-shaped member as one side of the occluding surface and a Teflon articulating member for the opposing side of the pressure control element. The silicone and the Teflon elements move and open relative to each other to allow passage of fluid under the application of a pressure differential across the element. These pressure control designs are functional, and each has advantages. Furthermore, they are embodied in a larger shunt configuration which involves either a unitized, contoured type base valve, exemplified by the Heyer-Schulte and the Pudenz-Schulte medical companies, which provide in one unitized construction a proximal occlusion, a dome structure for flushing or needling injection, a distal occluder, and a pressure control element with unitized nipple connectors on the proximal and distal end for connecting to the proximal and distal catheters of the shunt system. Descriptions of the use of this contoured or unitized shunt construction are given in the literature and in the brochures. Also in the patents cited above and in the literature there is discussion about how to use these valves and also how to fabricate, test, and perform quality assurance on these valves. Essential here is the method of pre-loading the diaphragm elements so that they will have a specific and reproducible pressure flow characteristic. In general, the description in the patents and the literature are based on stiffness of the diaphragm elements, variation in thickness, and topology of the diaphragm elements, pre-loading methods involving pre-loading and gluing the stems of mushroom-type diaphragm elements, and sample selection of lots and devices. It is also described in the Heyer-Schulte and PS Medical brochures that their contoured valve has a unitized inner platform or body which is made of a relatively hard material, such as polypropylene. This body has a predetermined shape or contour as one looks at it in side section, the idea being that this contour will match the contour of the patient's skull, which is relatively curved when the shunt is implanted. Throughout their literature and patents they teach the use of this firm body with distal and proximal ports for digital or manual flushing of the valve, either proximally or distally, by means of finger pressure on the occluder at either the proximal or distal end followed by pressure on the flexible dome reservoir to flush it. Proximal and distal flushing are also described in the function of the Radionics shunt.
It is an objective of the present invention to provide a shunt valve configuration which has separate proximal occlusion internal body and separate distal occlusion inner body so that the articulation of the shunt can conform to the individualized contour of the patient's skull, unlike the fixed body or unitized body design of Heyer-Schulte and Pudenz-Schulte companies.
Another objective of the present invention is to provide a substantially planar or somewhat convex diaphragm shape which occludes against a non-planar surface of different material to constitute the pressure flow controlling element and reflux control closing element. By means of such an essentially planar diaphragm configuration, together with a non-planar opposing surface, facilitation of testing can be done both visually and by pre-loading of the diaphragm stem or other structure.